console.log('1')
setTimeout(() => {
  console.log('2')
})
new Promise((resolve, rejects) => {
  console.log('3')
  resolve()
}).then(() => {
  let i = 0
  while(i < 1000000000) {
    i++
  }
  console.log('4')

})
let i = 0
while(i < 1000000000) {
  i++
}
console.log(5)

